Multispectral band sensor

ABSTRACT

Devices, methods, systems, and computer-readable media for a multiband detector are described herein. One or more embodiments include a multiband detector designed to detect an emission source including a broadband lens, a broadband detector, and a filter that allows electromagnetic radiation entering the system to be filtered into at least two wavelength bands before contacting the broadband detector wherein one or more wavelength bands are used to determine system functionality and wherein one or more other wavelength bands are used to identify the presence of an emission source having a characteristic particular wavelength or wavelength range.

PRIORITY INFORMATION

This application is a continuation of U.S. Non-Provisional applicationSer. No. 15/258,885, filed Sep. 7, 2016, which claims the benefit ofU.S. Provisional Application No. 62/314,202, filed Mar. 28, 2016, thecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to methods, devices, systems, andcomputer-readable media for a multiband detector.

BACKGROUND

It is desirable to detect flames for early alarming of a fire. A typicalmethod is that of triple-infrared (IR) which involves three detectors:one tuned to the 4.4 micrometer (μm) carbon dioxide emission band line(such emissions are formed when hydrocarbons burn) and the other twodetectors are tuned to off-band lines, to discriminate between a flameand hot objects. These broadband detectors typically look at a 90 degreefield of view, but are not capable of discerning individual sources ofradiation within that field of view.

Another approach is to use an imager so that the camera can betterdiscriminate between a flame and hot objects within the field of view.An imager makes it possible to see flames even when there are other hotobjects in the field of view that are in different locations.

However, there are several potential problems with such a solution. Forexample, in some instances, the optics may get coated with debris, suchas oil or soot) or an object may be in the way of the field of view.This can impair the viewing of a flame and/or its identification.

It is also desirable to look at objects in the field of view and discernwhether these objects are emitted at 4.4 μm which may be an indicator ofa flame, rather than just a hot item in the field of view. To do thiscurrently requires the use of a filter wheel capturing separate imagesat the two spectral bands, but the moving parts associated with suchfilters can lead to failure.

Further, although the detectors can detect a flame, the detectors haveno ability to locate the flame with respect to other objects in the areaof the field of view, so a system like this can identify that there is aflame, but not its location.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example of a system for a multiband detector according toone or more embodiments of the present disclosure.

FIG. 2 is an example of a field of view for a multiband detectoraccording to one or more embodiments of the present disclosure.

FIG. 3 is an example of a diagram of a computing device for a multibanddetector according to one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

Devices, methods, systems, and computer-readable media for a multibanddetector are described herein. One or more embodiments include amultiband detector designed to detect an emission source including abroadband lens, a broadband detector, and a filter that allowselectromagnetic radiation entering the system to be filtered into atleast two wavelength bands before contacting the broadband detectorwherein one or more wavelength bands are used to determine systemfunctionality and wherein one or more other wavelength bands are used toidentify the presence of an emission source of having a characteristicparticular wavelength or wavelength range.

The multiband detector as described herein is capable of detecting atleast two spectral bands in order to detect a flame with one band and toprovide a secondary function with one or more other bands. As usedherein, a wavelength band is a group of desired wavelengths orwavelengths around a desired wavelength, such as around 4.4 micrometers,for example, while a wavelength range is a range of wavelengths withinthe electromagnetic spectrum (e.g., MWIR or LWIR wavelength ranges orwavelength ranges emitted by a source). Also as used herein the MWIRrange includes wavelengths between 3-5 micrometers and the LWIR rangeincludes wavelengths 8 micrometers and above.

As indicated above, some of the functions that can be provided include:to determine the presence of an emission source (e.g., a flame) having acharacteristic particular wavelength (e.g., 4.4 micrometers, ischaracteristic of a hydrocarbon based flame) or wavelength range (e.g.,4.1 to 4.7 micrometers, can be defined as indicative of a hydrocarbonflame), determine a location of a number of emission sources, and/ordetermine a detection problem with the system or an object in the fieldof view as discussed above.

Any suitable broadband detection array can be used as the broadbanddetector. For example, an array that can detect at least two desiredimaging bands (i.e., radiation wavelength ranges) can be utilized.

In some embodiments, a bolometer can be used to provide the broadbanddetector. Using a bolometer can be beneficial, for example, because itis a low cost device that will provide the necessary broadbandcharacteristics for use as a broadband detector.

In various embodiments, the broadband detector array is a bolometer thatoperates over mid-wavelength infrared (MWIR) and long wavelengthinfrared (LWIR) bands. Further, in some such embodiments, the lens canbe a MWIR-LWIR transmitting lens.

In some embodiments, the filter allows a first wavelength band within aMWIR and a second wavelength band within a LWIR to pass through thefilter to the detector.

As discussed herein, in some embodiments, the emission source is a flameand the multiband detector system can be used as a flame detector. Thiscan be accomplished, for example, by utilizing a filter wherein one ofthe at least two wavelength bands that passes through the filterincludes 4.3 micrometers or 2.7 micrometers.

In some embodiments, the broadband detector can detect (e.g., sense,etc.) wavelength bands within the mid-wavelength infrared (MWIR) andwavelength bands within the long wavelength infrared (LWIR). That is,the dual band broadband detector can detect one or more specific bandswithin the MWIR and one or more specific bands within the LWIR.

The multiband detector as described herein can include a common lens andthe resultant field of view (FOV) will be the same when viewing the LWIRand the MWIR data. This can be beneficial, for example, in identifyingthe location of a flame with respect to other items within the FOV asthe viewpoints of the sets of data will be the same. In someembodiments, the lens can be a wide FOV MWIR-LWIR lens. This can allowfor the detector to monitor a larger area, among other benefits.

In some embodiments, the multiband detector can include a singleMWIR-LWIR filter that can include a number of wavelength bands withinthe MWIR and a number of wavelength bands within the LWIR to allowdesignated ranges within the MWIR and LWIR to pass through the filter tothe broadband detector. In various embodiments, the multiband detectorcan include one or more MWIR filters and one or more LWIR filters or oneor more MWIR-LWIR filters.

In some embodiments, each pixel in the broadband detector can detectboth the MWIR and LWIR wavelength ranges. This can be beneficial, forexample because it allows a composite image formed from both the MWIRand LWIR data and thereby allowing a viewer or the computing device tobetter identify the location of the flame with respect to other items inthe field of view.

In various embodiments, the multiband detector can detect the MWIRemissions from a flame on a pixel by pixel basis. This can be beneficialbecause a flame may be small, but could be detected by such embodiments.Another benefit is that the system could identify multiple flame sourcesbased on the pixel data.

In some embodiments, the filter can allow specific wavelength ranges topass through to the filter. For example, in some embodiments, thespecific wavelength ranges can correspond to one or more unique flameemission wavelengths or wavelength ranges within the MWIR (e.g., carbondioxide at 4 micrometers, hydrogen flame at 2.7 micrometers, or rangessuch as 3.8-4.2 micrometers for a carbon dioxide flame and 2.2-3.2micrometers for a hydrogen flame, etc.). If one or more ranges are used,the range can be determined based on whether the range will suitablyidentify the flame with respect to other items that may emit radiationwithin that range.

In some embodiments, the filter can be utilized to block MWIR radiationfrom other sources (e.g., sun, etc.). In addition, the LWIR can bereceived by the broadband detector to ensure that the multiband detectoris functioning properly.

For example, the LWIR can be utilized to provide a failsafe for themultiband detector if the detector is malfunctioning or if the lens hasbecome obscured for some reason. For instance, if the MWIR range is notdetecting a flame, the LWIR data can be checked to see if the detectoris detecting something. If it is also not detecting anything, then thelens may be obscured or there may be another problem with the system andsomeone should be alerted to communicate via a computing device orinitiate a physical inspection to check the system. It may also be thatthe detector is being saturated with data which can be identified by thesystem and addressed in a similar manner to the process described above.

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof. The drawings show by wayof illustration how one or more embodiments of the disclosure may bepracticed.

These embodiments are described in sufficient detail to enable those ofordinary skill in the art to practice one or more embodiments of thisdisclosure. It is to be understood that other embodiments may beutilized and that process changes may be made without departing from thescope of the present disclosure.

As will be appreciated, elements shown in the various embodiments hereincan be added, exchanged, combined, and/or eliminated so as to provide anumber of additional embodiments of the present disclosure. Theproportion and the relative scale of the elements provided in thefigures are intended to illustrate the embodiments of the presentdisclosure, and should not be taken in a limiting sense.

The figures herein follow a numbering convention in which the firstdigit corresponds to the drawing figure number and the remaining digitsidentify an element or component in the drawing. Similar elements orcomponents between different figures may be identified by the use ofsimilar remaining digits.

As used herein, “a” or “a number of” something can refer to one or moresuch things. For example, “a number of devices” can refer to one or moredevices. Additionally, the designator “N”, as used herein, particularlywith respect to reference numerals in the drawings, indicates that anumber of the particular feature so designated can be included with anumber of embodiments of the present disclosure.

FIG. 1 is an example of a system 100 for a multiband detector accordingto one or more embodiments of the present disclosure. In someembodiments, the system 100 can include a lens 104, a filter 107, and abroadband detector 106. In some embodiments, the broadband detector 106can include a broadband detector window 108 and a broadband detectorarray 110. In some embodiments, the broadband detector array 110 can becoupled to a computing device (e.g., computing device 330 as referencedin FIG. 3).

In some embodiments, radiation 102-1 consisting of a plurality ofwavelengths (e.g., all wavelengths, background radiation source,radiation source, flame source, etc.) can be received by the lens 104.The radiation 102-1 can includes MWIR and LWIR wavelengths, as describedherein. In some embodiments, the lens 104 can be a wide field of view(FOV) MWIR-LWIR lens. In some embodiments, the lens 104 can focus thereceived radiation 102-1 at filter, as radiation 102-2.

In some embodiments, the filter 107 can be a filter with designatedwavelength bands. In some embodiments, the designated wavelength bandscan include wavelength bands for designated wavelength ranges.

For example, the filter 107 can include designated bands to allowspecific wavelength ranges to pass through the filter. In someembodiments, the specific wavelength ranges can correspond to uniqueflame emission wavelengths within the MWIR (e.g., carbon dioxide at 4micrometers, hydrogen flame at 2.7 micrometers, etc.) or ranges, asdiscussed above. The filter 107 can be used, to block particularwavelength ranges from the radiation 102-2 and allow radiation 102-3 topass through the filter 107.

As described herein, the filter 107 can include designated wavelengthbands within the MWIR and designated wavelength bands within the LWIR orthe filters could be separate components, with one handling a first setof wavelengths (e.g., MWIR) and one or more others handling otherwavelengths (LWIR). In some embodiments, the bands within the MWIR canbe utilized by the broadband detector array 110 to identify a number offlames over a wide field of view. For example, the flames can beprimarily combustion of one or more of: carbon dioxide, methane,propane, propylene gas, Volatile Organic Compound (VOC) and/or hydrogen.

In some embodiments, the filter 107 can be configured such that thetransmittance of the MWIR bands and the LWIR bands are matched with thedynamic range of the broadband detector array 110. For example, thetransmittance of filter 107 (what wavelengths are allowed to passthrough the filter) can be configured to be uniform across all spectralbands (e.g., approximately 1.0) for a low dynamic range broadbanddetector (e.g., 8 or 10 bits resolution). In this manner, the image maybe granular, but the items (flame and/or other items in the FOV) can beidentified.

In some embodiments, the transmittance of the bands including LWIR andMWIR are purposely designed to have different transmittance levels. Thiscan be particularly useful for a high dynamic range broadband detector,such as one with 14 bits or more in each sensing element or pixel. Thefilter 107 can enable direct relationships between specific intensityranges and the radiation from each pass band.

For example, a 6000-7000 intensity range of raw detector counts cancorrespond to radiation of a hydrogen carbon flame (HC) at 4.4micrometers and a 1000-2000 intensity range can be due to LWIR broadbandof background at 300K. Other intensity ranges to spectral bands pair caninclude, for example: 3000-4000 for a hydrogen flame (H2), 4000-6000 fora H2+LWIR background, 7000-9000 for a hydrocarbon (HC)+LWIR background,9000-11000 for HC+H2, and a 10000-13000 for HC+H2 flame+LWIR background.

In some embodiments, the filter 107 can be configured to be in front ofthe lens 104. This can be beneficial in applications where the samemultiband detector may be used to detect different things. In suchembodiments, one filter that is designed to pass one or more particularwavelengths or wavelength ranges can be interchanged with another filterdesigned to pass one or more different particular wavelengths orwavelength ranges. As discussed above, a single or multiple filters maybe used in the embodiments of the present disclosure and in someembodiments, one or more of the filters may be removable and/orinterchanged with other filter types. Further, in some embodiments,filters that are between the lens and the detector can be removed and orinterchanged (e.g., a slit or door may be placed in a housing having thefilter therein and the filter may be removed among other removaldesigns).

The input radiation 102-1 can be filtered by filter 107, which passesthe radiation 102-2 having two or more designated wavelengths. Lens 104can focus the radiation 102-2 to the detector 106 as radiation 102-3.

In some embodiments, the system 100 can include a broadband detector 106that has a housing to encase the broadband detector array 110. In someembodiments, the broadband detector 106 can utilize a window 108 toallow radiation 102-3 to pass through to the broadband detector array110. In some embodiments, the window 108 can be transparent to MWIR-LWIRto allow both MWIR and LWIR wavelengths through to the broadbanddetector array 110.

In some embodiments, the broadband detector 106 can include a broadbanddetector array 110 that is coupled to a computing device. Suchembodiments are beneficial, for example, because additional functionscan be provided by the computing device based on analysis of the datafrom the detector array.

In some embodiments, the broadband detector array 110 can be a focalplane array that provides a relatively high dynamic sensitivity range.In some embodiments, the broadband detector array 110 can be a bolometerthat can include a dynamic range of 12 to 14 bit pixels or valuesranging from 0 to 4096 or 0 to 16384, respectively. In some embodiments,the broadband detector array 110 can have a relatively flat responseacross a broad spectrum of wavelengths.

In some embodiments, the LWIR region of the received radiation 102-3 canbe utilized as a failsafe for the system 100. In some embodiments, theLWIR region of the received radiation 102-3 can be thermal wavelengthsof the FOV. In various embodiments, the LWIR region of the receivedradiation 102-3 can be utilized to ensure that the system 100 isfunctioning properly.

For example, when the broadband detector array 110 does not detect anyflames via the MWIR as described herein, the LWIR region can be utilizedto ensure that the broadband detector array 110 is functioning. In thisexample, the broadband detector array 110 may not detect flames via theMWIR due to a malfunction instead of a lack of flames in the area. Suchfailsafe functionality can be accomplished in this manner because thereshould always be LWIR radiation from any object of a reasonable ambienttemperature.

In various embodiments, the LWIR region of the received radiation 102-3can be utilized to identify a number of failure modes (e.g.,obstructions between the radiation 102-1 and the broadband detectorarray 110, etc.). In some embodiments, the number of failure modes caninclude, but are not limited to: oil, soot, or other residue on the lens104, a stationary or moving object that is partially or completelyblocking the FOV, residue on the window 108 or filter 107, among othercauses that can block or alter the radiation 102-1 from reaching thebroadband detector array 110.

In some embodiments, the broadband detector array 110 can be a twodimensional (2D) array. In some embodiments, the lens 104 can focus theradiation 102-1 onto only a few pixels of the broadband detector array110. For example, the lens 104 can focus the radiation 102-1 through thefilter 107 and to the pixels within area 109 of the broadband detectorarray 110. This can be beneficial, for example, to reduce the size ofthe array or to allow other parts of the array to be used for otherfunctions, among other benefits.

In previous systems and methods, the wavelengths were focused onto asingle detector that observed an entire FOV. In some embodiments of thepresent disclosure, the broadband detector array 110 can be designed todetect only wavelengths transferred through the filter 107. That is,only the wavelength bands allowed to pass through the filter 107 aredetectable by the broadband detector array 110. In some embodiments, thebroadband detector array 110 may not be able to analyze the spectralmakeup of the radiation 102-3, but may be able to identify whenparticular wavelengths within the radiation 102-3 are present (e.g., itcan indicate of a flame is present or not, but the data is not analyzedbeyond that indication).

In some embodiments, the broadband detector array 110 can be utilized tonotify a user of the system 100 that there has been a failure. Asdescribed herein, the failure can be a malfunction of the broadbanddetector array 110, an obstruction or interference blocking theradiation 102-1, or other malfunction of the components of the system100 that can interrupt the functionality of the broadband detector array110. The absence of LWIR or a significant change in the LWIR backgroundsignal or imagery (this can be determined by comparison of data setsfrom the detector from different moments in time to identify changesbetween the data sets) can indicate a system failure.

FIG. 2 is an example of a field of view 220 for a multiband detectoraccording to one or more embodiments of the present disclosure. In someapplications of the embodiments of the present disclosure, the field ofview 220 can, for example, be an area of an oil refinery or other areathat includes a number of flames 222-1, 222-2. As described herein, anumber of obstructions 224, 226 can be within the field of view 220.

In previous systems and methods, narrow bands of MWIR are used fordetection of flames. In the absence of a flame, the received narrow bandMWIR radiation is low, resulting in little or no signal.

The number of obstructions 224, 226 could block radiation from reachingthe detector resulting in little or no signal. Thus, previous detectorshad no way to differentiate between a blocked broadband detector and anormal situation with no flame. Thus, the previous detector systemscould not indicate that there are no flames within the field of view 220when the broadband detector was blocked.

In some embodiments, the multiband detector as described herein canidentify the number of obstructions 224, 226 utilizing the received LWIRfrom the field of view 220. Broadband detector array 110 outputsintensity, I_(tot) (t) of the radiation 102-3, which consists of narrowbands of MWIR and broad band of LWIR at time t. (i.e., I_(tot)(t)=I_(MWIR) (t)+I_(LWIR) (t)).

In the presence of flames, I_(MWIR) (t) is significantly bigger thanI_(LWIR) (t). While I_(tot) (t) is approximately equal to I_(MWIR) (t).

In some embodiments, this can be utilized to detect flames. In theabsence of a flame, the sensed intensity consists of the LWIR radiationof the FOV. An obstruction causes I_(tot) (t) to be zero orsignificantly lower (e.g., oil on the lens) than the normal LWIRintensity at previous time, I_(LWIR) (t0). Major changes betweenI_(LWIR) (t0) and I_(LWIR) (t1) can indicate a failure mode of thesystem 100 as referenced in FIG. 1.

For example, the obstruction 224 can be a residue (e.g., oil, dust, mud,etc.) that is on a lens of the multiband detector. In this example, themultiband detector can identify an obstruction 224 on the lens andnotify a user of the obstruction due to a decrease in I_(tot) (t).

In another example, the obstruction 224 can be a vehicle that has parkedin front of the multiband detector blocking the field of view 220. Inthis example, the multiband detector can identify the obstruction 226and notify a user of the obstruction.

In some embodiments, the field of view 220 can include desired flamesources 222-1 and undesired flame sources 222-2. For example, thedesired flame sources 222-1 can include controlled flames within an oilrefinery. The desired flames can be flames that are utilized to burn offexcess materials. In another example, the undesired flame sources 222-2can be unintended flames that can cause damage to the oil refinery. Insome embodiments, the desired flames can be identified and ignoredthrough use of instructions executed by the computing device whenanalyzing the data from the detector.

In some embodiments in which the broadband detector array 110 is a 2Dfocal plane array (e.g., bolometer), the bands within the MWIR can beutilized to identify desired flames (e.g., controlled flames) andundesired flames (e.g., uncontrolled flames). The intensity ouput fromthe broadband detector array 110 is not the intensity of the totalradiation from the FOV, but is spatially distributed, which can berepresented as: I_(tot) (t,x,y)=I_(MWIR) (t,x,y)+I_(LWIR) (t,x,y), wherex,y is a pixel location corresponding to an instantaneous field of view.

Detection of flame can be localized based on the x, y locations.Locations of known desired flame sources can be specified by users.Further analyses can compute the characteristics of the flame via thecomputing device including, but not limited to: the size, shape, and/orintensity distribution. With user designated locations of desiredflames, the desired flames can be ignored from the detected flames, thusnot alarming users of their presence.

Similarly, the locations of obstructions can be identified using a 2Dbroadband detector array 110. Partial or complete obstruction can bedetermined based on the size of the detected obstruction. Furtheranalyses can characterize the obstructions including, but not limitedto: the type, shape, and/or intensity distribution. The nature of theobstruction, e.g., smearing on the lens vs an oil tanker truck, can beclassified and used in the analysis of data by the computing device orfor other functions of the system.

By identifying the number of obstructions 224, 226, unnecessary repairsof the multiband detector can be avoided. For example, identifying thenumber of obstructions 224, 226 can be utilized to identify a cause offailures. In some embodiments, the field of view 220 can include anumber of flame sources 222-1, 222-2. Identification of the failure canalso aid in getting the proper response to such a failure (e.g., gettinga technician to clean the lens, getting someone to move the truck).

FIG. 3 is an example of a diagram of a computing device 330 for amultiband detector according to one or more embodiments of the presentdisclosure. Computing device 330 can be, for example, an embeddedcontroller as described herein, among other types of computing devices.

As shown in FIG. 3, computing device 330 includes a memory 332 and aprocessor 334 coupled to memory 332. Memory 332 can be any type ofstorage medium that can be accessed by processor 334 to perform variousexamples of the present disclosure. For example, memory 332 can be anon-transitory computer readable medium having computer readableinstructions (e.g., computer program instructions) stored thereon thatare executable by processor 334 to determine a deployment of an accesscontrol system in accordance with one or more embodiments of the presentdisclosure.

Memory 332 can be volatile or nonvolatile memory. Memory 332 can also beremovable (e.g., portable) memory, or non-removable (e.g., internal)memory. For example, memory 332 can be random access memory (RAM) (e.g.,dynamic random access memory (DRAM) and/or phase change random accessmemory (PCRAM)), read-only memory (ROM) (e.g., electrically erasableprogrammable read-only memory (EEPROM) and/or compact-disc read-onlymemory (CD-ROM)), flash memory, a laser disc, a digital versatile disc(DVD) or other optical disk storage, and/or a magnetic medium such asmagnetic cassettes, tapes, or disks, among other types of memory.

Further, although memory 332 is illustrated as being located incomputing device 330, embodiments of the present disclosure are not solimited. For example, memory 332 can also be located internal to anothercomputing resource (e.g., enabling computer readable instructions to bedownloaded over the Internet or another wired or wireless connection).

As discussed herein, a computing device can be in communication with thebroadband detector to provide a fail safe function which determineswhether the system is operating correctly based on data received fromthe broadband detector. The data received can, for example be sense datafrom sensors that are arranged in an array to form the detector.

The data can be transferred from the detector array to the computingdevice. This data can then be analyzed, for example, by executableinstructions stored in memory to determine whether an emission source ispresent in the FOV, the location of the emission source, and/or whetherthe system is working properly (i.e., fail safe function), among otherfunctions.

In some embodiments, the fail safe function is based on a wavelengthband within the LWIR wavelength range and the emission source can beidentified based on the MWIR wavelength range data. In this manner, thecomputing device can process both types of data and can provide bothfunctions, in some embodiments. In addition to analysis, the computingdevice can also include executable instructions to alert a user of asystem failure based on the determination of whether the system isoperating correctly.

As shown in FIG. 3, computing device 330 can also include a userinterface 336. User interface 336 can include, for example, a display(e.g., a screen, an LED radiation, etc.). The display can be, forinstance, a touch-screen (e.g., the display can include touch-screencapabilities). User interface 336 (e.g., the display of user interface336) can provide (e.g., display and/or present) information to a user ofcomputing device 330.

The display can be used to view the data from the broadband detector.For example, the computing device can receive the data and instructionscan be executed to show the received data on the display. In someembodiments, the display can be used to view the MWIR and LWIR dataseparately, and in some embodiments, the data can be viewed at the sametime on the display. Further, as discussed herein, executableinstructions can be used to exclude certain areas of data (e.g., desiredflames) from the display or from having an alert or alarm initiated.

Additionally, computing device 330 can receive information from the userof computing device 330 through an interaction with the user via userinterface 336. For example, computing device 330 (e.g., the display ofuser interface 336) can receive input from the user via user interface336. The user can enter the input into computing device 330 using, forinstance, a mouse and/or keyboard associated with computing device 330,or by touching the display of user interface 336 in embodiments in whichthe display includes touch-screen capabilities (e.g., embodiments inwhich the display is a touch screen).

As used herein, “logic” is an alternative or additional processingresource to execute the actions and/or functions, etc., describedherein, which includes hardware (e.g., various forms of transistorlogic, application specific integrated circuits (ASICs), etc.), fieldprogrammable gate arrays (FPGAs), as opposed to computer executableinstructions (e.g., software, firmware, etc.) stored in memory andexecutable by a processor.

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art will appreciate that anyarrangement calculated to achieve the same techniques can be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments of thedisclosure.

It is to be understood that the above description has been made in anillustrative fashion, and not a restrictive one. Combination of theabove embodiments, and other embodiments not specifically describedherein will be apparent to those of skill in the art upon reviewing theabove description.

The scope of the various embodiments of the disclosure includes anyother applications in which the above structures and methods are used.Therefore, the scope of various embodiments of the disclosure should bedetermined with reference to the appended claims, along with the fullrange of equivalents to which such claims are entitled.

In the foregoing Detailed Description, various features are groupedtogether in example embodiments illustrated in the figures for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the embodiments of thedisclosure require more features than are expressly recited in eachclaim.

Rather, as the following claims reflect, inventive subject matter liesin less than all features of a single disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate embodiment.

1. A filter, comprising: wavelength bands to allow electromagneticradiation entering the filter to be filtered into at least twowavelength ranges before contacting a detector to identify a presence ofan emission source having a particular wavelength range.
 2. The filterof claim 1, wherein one of the at least two wavelength ranges are usedto determine a functionality of a system.
 3. The filter of claim 1,wherein the detector is a bolometer that operates over mid-wavelengthinfrared (MWIR) and long wavelength infrared (LWIR) ranges.
 4. Thefilter of claim 1, wherein the emission source is a flame.
 5. The filterof claim 1, wherein one of the wavelength ranges is 4.3 micrometers or2.7 micrometers.
 6. The filter of claim 1, wherein a spectraltransmission of the filter is set such that a first wavelength range ofelectromagnetic radiation from an emission source has a differentintensity than a second wavelength range of electromagnetic radiationfrom the emission source.
 7. The filter of claim 5, wherein a firstwavelength range and a second wavelength range is used to determine afail safe condition.
 8. The filter of claim 1, wherein the filterincludes a narrow band transmission between 4.3 and 4.7 micrometers(μm).
 9. A system for a multiband detector, comprising: a filter toallow a first wavelength band of electromagnetic radiation within amid-wavelength infrared (MWIR) range and a second wavelength band ofelectromagnetic radiation within a long wavelength infrared (LWIR)range; and a computing device coupled to a detector to provide detectionof an emission source based on received transmitted radiation from thefirst wavelength band within the MWIR range and a fail safe operationbased on the received transmitted radiation from the second wavelengthband within the LWIR range.
 10. The system of claim 9, wherein thedetector is a bolometer that detects both the first and secondwavelength bands at each pixel of the bolometer.
 11. The system of claim9, comprising an imaging lens coupled to the filter.
 12. The system ofclaim 9, wherein the computing device determines whether the presence ofthe emission source having characteristics in the first wavelength bandbased on data received from the detector.
 13. The system of claim 9,wherein the LWIR of the received transmitted radiation is utilized bythe computing device to determine an existence of obstructions betweenthe radiation and the broadband detector.
 14. The system of claim 13,wherein the computing device determines the existence of obstructions bycomparing data sets from the detector at different points in time.
 15. Asystem for a multiband detector, comprising: a lens to receive radiationfrom a field of view for an area; a filter to receive radiation from thelens, wherein the filter allows a first wavelength band within amid-wavelength infrared (MWIR) and a second wavelength band within along wavelength infrared (LWIR) to pass through the filter; a broadbanddetector to receive transmitted wavelengths from the filter; and acomputing device coupled to the broadband detector to determine anexistence of obstructions of radiation received by the lens.
 16. Thesystem of claim 15, wherein the MWIR received by the broadband detectoris utilized by the computing device to identify a number of flames overthe complete field of view.
 17. The system of claim 15, wherein the MWIRis detected on a pixel by pixel basis by the computing device.
 18. Thesystem of claim 15, wherein MWIR and LWIR bands are matched with adynamic range of the broadband detector such that the wavelength bandsare uniform across all spectral bands.
 19. The system of claim 15,wherein the computing device determines when an obstruction exists onthe lens when the computing device determines an absence of LWIRreceived at the broadband detector.
 20. The system of claim 15, whereinthe broadband detector has an 8 bit resolution.